A coin chute assembly may typically include a stationary housing having a horizontally oriented guide track, a vertically oriented mounting plate and a baffle positioned over a set of blocking dogs. A coin slide is slidably mounted in the guide track of the housing to move into and retract from the housing. Slots provided in the upper surface of the coin slide support a requisite number and denomination of coins in a vertical, longitudinally oriented position. Without the coins, the coin slide is prevented from moving inwardly beyond a point where the blocking dogs catch a bar mounted on the coin slide. The coins coact with a sizing block mounted in a forward end of the baffle to push the blocking dogs downwardly, thus facilitating further inward movement of the coin slide. Eventually, a fixed finger of an extension mounted on the coin slide engages an "on" switch timer or other structure provided for activation of the machine.
After the coins pass under the sizing block, a pawl mounted in the side of the coin slide comes into cooperative engagement with a rack mounted on the side of the guide track. The pawl and rack provide a ratchet mechanism that prevents the coin slide from being retracted until after the coin slide moves inwardly to a point where the coins fall into a coin box.
Generally, at the point where the coin slide is extended far enough to engage the start mechanism of the associated machine, such as a dryer, washer, vending machine, etc., the coins have not yet dropped through the slots in the coin slide and into the coin box. At this point, a tampering customer can pry backwards on the handle of the coin slide, using the top edge of the meter case or "shoe-box" for leverage. After prying with sufficient force, the coin slide pawl is damaged or broken so that the coin slide can be freely reciprocated. Once this occurs, the "customer" can receive a free start by pushing the coin slide inwardly sufficiently to activate the machine, without reaching the point where the coins fall into the coin box. Then, the coin slide is retracted to retrieve the coins.
Generally, the amount of coin slide travel necessary to effect activation of the machine is relatively slight. Once the ratchet mechanism is broken or otherwise disarmed, the tampering customer can leave the coin slide in, even after discharge of the coins into the coin box, and start the machine by reciprocating the coin slide in and out a relatively short distance. As long as the coin slide is not retracted far enough to re-engage the blocking dogs, free starting can occur indefinitely. This problem is at least partly attributable to the generally short "engage-to-start" stroke of the slide extension. Normally, the activation finger is fixed and need only contact a timer or switch mechanism for a relatively short travel distance of the coin slide.
A coin chute assembly having the aforementioned features including the coin slide and blocking dogs is described in U.S. Pat. No. 4,502,584 to Lambiris. A coin slide extension assembly capable of use on the coin slide of the Lambiris patent is found in U.S. Pat. No. 3,872,958 to Greenwald et al. Both of these patents are incorporated herein by reference. Other U.S. patents describing general features of coin slides and anti-tampering mechanisms include U.S. Pat. Nos. 2,947,186 to Greenwald; 4,131,190 to Gitlin; 4,588,064 to Monfredi 4,651,861 to Lambiris; 4,828,096 to Gitlin et al; and 5,074,396 to Gitlin et al, the disclosures of which are also incorporated herein by reference.